The present invention relates to communications networks, particularly but not exclusively communications networks for providing mobile telephone communication, and to methods of operating such networks.
Mobile communications as a concept embraces not only mobility of a user within his home network, but also the ability for callers to he able to communicate with that user when he has moved to, i.e. registered with, a remote network, referred to as a visited network. This is known as roaming. On a global scale, one can talk about a global mobile network comprising a multiplicity of national mobile networks interconnected by international links.
Callers dial the user""s globally unique telephone number, and their calls are, routed to the user""s home network, where a register is kept of the current locations of all the users having telephone numbers associated with that home network, and that call is then extended to the user""s visited network. This is referred to as tromboning, i.e. the call goes into the home network and out to the visited network, with attendant international call charges and extended call set up units, and it happens even when the caller is in that visited network.
Also, if a roaming user accesses a messaging service in his home network and retrieves his messages, which might be voice or multimedia format, each of these has to be transmitted in real time over international links, and could be subject to congestion.
U.S. Pat. No. 6,038,456 (Colby et al.) discloses a solution to the problem of issuing a user with another mobile telephone number (MSISDN) for use for, e.g. data calls, when the Home Location Register (HLR) unit which records that user""s original MSISDN has no spare. Instead of the known practice of a network operator (carrier) ordering a large quantity of phones from a supplier, say 1000, and associating a corresponding block of MSISDNs with a particular HLR unit, Colby et al. propose allocating MSISDNs to HLR units on an individual basis and having a lookup table (called a Register Unit) which signalling transfer points interrogate by the dialed MSISDN in order to find which HLR unit to access for the called user""s details.
U.S. Pat. No. 5,915,220 (Chelliah) discloses a mobile network in which the Home Location Register (HLR) has a last visited list of Mobile Switching Centres (MSC) and the deregistration procedure involving a Registration cancel Message is modified such that an MSC at which a user was previously registered does not delete the user""s service profile upon receipt from the HLR of a Registration Cancel Message. Thus, if the user revisits an MSC, the HLR knows from its last visited list that that MSC already stores a copy of the user""s service profile, and does not send another copy.
According to a first aspect of the present invention there is provided a method of operating a communications network interconnected with a plurality of other communications networks, the method comprising the steps of:
establishing data storage and a location register having entries comprising a user identifier and an associated location identifier; and
responding to an originating call to a called user by
accessing the location register in accordance with a user identifier for that called user to ascertain the corresponding associated location identifier, and it there is a corresponding entry, and
performing connection set up on the basis that the destination network for the called user is that communications network which corresponds to that ascertained location identifier;
the method being characterised in that:
user-associated relocatable data packages currently located at said communications network are stored in said data storage, and
each said location identifier represents the most recent location known to said communications network of the corresponding user-associate relocatable data package;
and the method being characterised by the steps of:
receiving from a said other communications network a move request in respect of a specified user, and in response,
removing that specified user""s associated relocatable data package from the data storage, and
relocating that data package to said other communications network.
The use of the location register and the relocatable data package alleviates the above described situations. The user""s relocatable data package can be relocated at a time convenient to the network operators, e.g. when there is little traffic between the home network and the visited network, and after it has been moved the user will then be able to retrieve his messages from a local storage of his data package, without involving any international links in his real time retrieval of the messages.
Preferably, there is included the step of responding to receipt from said other communications network of a location register update message in respect that specified user by changing the location identifier of that specified user""s entry to that for said other communications network.
There may be included the steps of:
receiving a request from a user, currently registered with said communications network as a visitor, for that visiting user""s associated relocatable data package to be relocated to said communications network;
in response to that receipt, accessing the location register in accordance with an identifier for that visiting user; and, if there is a corresponding entry,
ascertaining the location identifier of that corresponding entry, and
sending a move request in respect of that visiting user to the other communications network corresponding to the ascertained location identifier,
else, requesting of at least one of the other communications networks a location identifier for the other communications network currently storing that visiting user""s associated relocatable data package,
upon receipt of the requested location identifier, sending a move request in respect of that visiting user to the other communications network corresponding to the received location identifier; and
upon receipt of that user""s associated relocatable data package, storing it in the data storage.
According to a second aspect of the present invention there is provided a method of operating a communications network interconnected with a plurality of other communications networks, at least one of said other communications networks operating in accordance with the first aspect of the present invention, the method comprising the steps of:
receiving a request from a user, currently registered with said communications network as a visitor, for that visiting user""s associated relocatable data package to be relocated to said communications network;
in response to that receipt, requesting of at least one of the other communications networks a location identifier for the other communications network currently storing that visiting user""s associated relocatable data package;
upon receipt of the requested location identifier, sending to the other communications network corresponding to the received location identifier a move request for that user""s associated relocatable data package to be relocated to said communications network, and
upon receipt of that user""s associated relocatable data package storing it in association with a user identifier for that user.
There may be included the steps of retrieving instructions from a received user-associated relocatable data package, and in accordance with those instructions, effecting modification of each of a predetermined set of the communications networks.
Preferably, the step of effecting modification comprises generating a message and sending that message to each of said predetermined set of the communications networks other than that communications network which performs the step of retrieving instructions.
The retrieved instructions may comprise instructions for modifying the respective location registers by changing the respective stored location identifier to that of the network which performs the step of retrieving instructions.
The retrieved instructions may comprise instructions comprise instructions for storing call handling information and modifying the respective location registers to associate that stored call handling information with the entry corresponding to the received user-associated relocatable data package.
The requesting step may comprise sending a query message in respect of that visiting user to that one of said other communications networks which corresponds to the global address of that visiting user.
Alternatively, the requesting step may comprise sending a query message in respect of that visiting user to each of said other communications networks.
There may be included the steps of connecting calls for a particular user, whose user-associated relocatable data package is currently located at said communications network, to a message recording service and recording messages, and incorporating those recorded messages within that particular user""s relocatable data package.
According to a third aspect of the present invention there is provided a communications network arranged for interworking with a plurality of other communications networks and employing a global addressing scheme, the network comprising:
a location register arranged to store entries each comprising a user identifier and an associated location identifier; and
means arranged to respond to an originating call to a called user by
accessing the location register in accordance with an identifier for that called user and ascertaining the associated location identifier, and
performing connection set up on the basis that the destination network for the called user is that communications network which corresponds to that ascertained location identifier;
wherein the network is characterised by:
data storing means arranged to store user-associated relocatable data packages;
means arranged to respond to receipt from a said other communications network of a move request in respect of a specified user""associated relocatable data package stored in the data storing means by
removing that specified user""s associated relocatable data package from the data storing means, and
relocating that data package to said other communications network.
There may be included means arranged to respond to receipt from said other communications network of a message in respect of that specified user and containing location register update information by changing the location identifier of that specified user""s entry to that for said other communications network.
There may be included means arranged to respond to a request from a visiting user for that visiting user""s associated relocatable data package to be moved to said communications network, by
accessing the location register in accordance with an identifier for that visiting user,
and, if there is a corresponding entry,
ascertaining the associated location identifier, and
sending a move request in respect of that visiting user to a said other communications network corresponding to the ascertained location identifier, else
requesting of at least one of the other communications networks a location identifier for the other communications network currently storing that visiting user""s associated relocatable data package, and, upon receipt of the requested location identifier,
sending a move request in respect of that visiting user to that other communications network corresponding to that received location identifier.
According to a fourth aspect of the present invention there is provided a communications network arranged for interworking with a plurality of other communications networks, at least one of said other communications networks being in accordance with the third aspect of the present invention, said communications network comprising:
a location register arranged to store entries each comprising a user identifier and an associated location identifier; and
means arranged to respond to an originating call to a called user by
accessing the location register in accordance with an identifier for that called user and ascertaining the associated location identifier, and
performing Connection Set up on the basis that the destination network for the called user is that communications network which corresponds to that ascertained location identifier;
wherein the network is characterised by:
data storing means, and
means arranged to respond to a request from a user, currently registered with said communications network as a visitor, for that user""s associated relocatable data package to be moved to said communications network by
requesting of at least one of the other communications networks a location identifier for the other communications network currently storing that visiting user""s associated data package,
upon receipt of the requested network identifier, sending to the other communications network corresponding to the received location identifier a move request for that user""s associated data package to be relocated to said communications network, and
upon receipt of that user""s associated relocatable data package, storing it in said data storing means in association with a user identifier for that user.
There may be included means arranged to retrieve instructions from a received user""s relocatable data package, and in accordance with those instructions, to effect modification of each of a predetermined set of the communications networks.
Preferably, the retrieving and modifying means is arranged to effect said modification by generating a message and sending that message to each of said predetermined set of the communications networks other than itself.
Preferably, the retrieving and modifying means is arranged in accordance with those instructions, to modify the respective location register by changing the respective stored location identifier to its own location identifier.
Preferably, when a network of the present invention is for use when those instructions comprise instructions for storing call handling information, the retrieving and modifying means is arranged to modify the respective location register to associate such stored call handling information with the entry corresponding to the received user-associated relocatable data package.
A network of the present invention may be arranged to make said request of at least one of the other communications networks for said network identifier by sending a query message in respect of that visiting user to that one of said other communications networks which corresponds to the global address of that visiting user.
A network of the present invention may be arranged to make said request of at least one of the other communications networks for said network identifier by sending a query message in respect of that visiting user to each of said other communications networks.
A network of the present invention may have a message recording system, and included means arranged to respond to messages recorded by the message recording system in respect of a particular user whose relocatable data package is currently stored in said data storing means by incorporating those recorded messages within that particular user""s relocatable data package.